Global climate change, fossil energy resources that are becoming rarer and increasing energy prices have made the use of regenerative energies become increasingly significant over the past years with reference to energy policies and economy.
Highly efficient industries have been created in the area of the use of solar energy, for example. Today, photovoltaic modules or also solar thermal flat collectors are mostly mass-produced in a predominantly automated manner using robotized automation.
On principle, the same requirements for economization as have been observed for a long time in the automobile industry, e.g., are valid here and today.
This applies to the final step, in which the end products are combined to form storable, loadable and transportable stacks, to the same degree as to all preceding individual steps of the production process.
When in the past the question relating to the methods of module stacking had rather been a problem related to the transport from the manufacturer to the customer, which had to be solved in a packaging technology-related manner, a consequently economized production today demands for the relocation of the stacking process or of the stacking preparation, respectively, from the packaging storage facility into the end production hall.
In the end phase of the solar module production, the modules are adhered to their frame. After a brief, so-called “holding phase”, in which a certain contact pressure is applied, the adhesion process includes a so-called “hardening phase”, which extends over a longer period of time.
The invention is to make it possible to make the modules capable of still being stacked in this hardening phase, in that they are already at that point equipped with the elements of a stack holding system, which does not only ensure an economical storing of the module stacks in the operation of the manufacturer, but—without extensive additional packaging measures—also ensures a problem-free loading onto the transport means and a secure transport to the customer.
On principle, two forms of stacking are possible and common for the storage and the transport of photovoltaic modules or solar thermal flat collectors: the stacking in horizontal and in vertical position.
In the case of the horizontal stacking, the use side of the modules can either be arranged facing up (“sunny side up”) or down (“sunny side down”).
In the case of the vertical stacking, the modules, which are generally formed so as to be elongate-rectangular, can either be positioned with the longer side in vertical direction (upright) or with the shorter side in vertical direction.
Which form of stacking is to be preferred in the individual case can depend on different factors, such as, e.g., the size, weight and format of the modules, the measurements of the pallets to be used, the characteristic of the floor conveying and storage technology in the operation of the manufacturer or also on the best possible loading height use of the transport vehicles.
It was an essential goal of the invention to create a uniform, material-sparing holding system, which can be reused for the highest possible number of storage and transport cycles, and which can be used in equal measure for the horizontal as well as for the vertical stacking forms.
Furthermore, the following requirements had to be fulfilled:                The individual elements of the reusable holding system should be designed as being molded parts, which are as small, handy and light as possible, so as not to complicate their return shipment from the customer to the manufacturer.        The molded parts should be capable of being stressed to a high degree, because the total stress of the modules stacked on top of one another must be accommodated by the holding system and transferred onto the pallet at least in the case of the horizontal stacking.        
Chronologically, the individual molded parts of the holding system should not be attached to the frames of the individual modules by means of lateral attachment not only in the course of the actual stacking process, but prior to the actual stacking. A locking device is to ensure that the attached molded parts do not detach from the frame, but remain connected thereto even when the module is lifted, when the module is tilted from the horizontal into the vertical position or when the module is turned over by 180°.
These requirements led to the concept of a holding system for horizontal or vertical stacking of photovoltaic or solar thermal flat modules, which is comprised of individual molded parts, which are made of plastic and which are produced by means of an injection molding process and which can be connected among one another by means of mechanical cogging and which can be connected to form stabile vertical pillars or horizontal rails by means of locking to the module frame.